The invention relates to pulsed oximeters used to measure blood oxygenation.
The current trend towards mobile oximeters has brought the problem of how to minimize
power consumption without compromising on the performance of the device. To tackle
this problem, the present invention provides a method for controlling optical power
in a pulse oximeter. The signal-to-noise ratio of the received baseband signal
is monitored, and the duty cycle of the driving pulses is controlled in dependence
on the monitored signal-to-noise ratio, preferably so that the optical power is
minimized within the confines of a predetermined lower threshold set for the signal-to-noise
ratio. In this way the optical power is made dependent on the perfusion level of
the subject, whereby the power can be controlled to a level which does not exceed
that needed for the subject.
